MoImd4 mediates crosstalk between MoPdeH-cAMP signalling and purine metabolism to govern growth and pathogenicity in Magnaporthe oryzae |
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| Authors: | Lina Yang Yanyan Ru Xingjia Cai Ziyi Yin Xinyu Liu Yuhan Xiao Haifeng Zhang Xiaobo Zheng Ping Wang Zhengguang Zhang |
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| Institution: | 1. Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095 China;2. Departments of Pediatrics, and Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112 USA |
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| Abstract: | The high-affinity cyclic adenosine monophosphate (cAMP) phosphodiesterase MoPdeH is important not only for cAMP signalling and pathogenicity, but also for cell wall integrity (CWI) maintenance in the rice blast fungus Magnaporthe oryzae. To explore the underlying mechanism, we identified MoImd4 as an inosine-5′-monophosphate dehydrogenase (IMPDH) homologue that interacts with MoPdeH. Targeted deletion of MoIMD4 resulted in reduced de novo purine biosynthesis and growth, as well as attenuated pathogenicity, which were suppressed by exogenous xanthosine monophosphate (XMP). Treatment with mycophenolic acid (MPA), which specifically inhibits MoImd4 activity, resulted in reduced growth and virulence attenuation. Intriguingly, further analysis showed that MoImd4 promotes the phosphodiesterase activity of MoPdeH, thereby decreasing intracellular cAMP levels, and MoPdeH also promotes the IMPDH activity of MoImd4. Our studies revealed the presence of a novel crosstalk between cAMP regulation and purine biosynthesis in M. oryzae, and indicated that such a link is also important in the pathogenesis of M. oryzae. |
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| Keywords: | GTP biosynthesis inosine-5′-monophosphate dehydrogenase Magnaporthe oryzae pathogenicity phosphodiesterase |
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